Tissue plasminogen activator modulates the cellular and behavioral response to cocaine

Cocaine exposure induces long-lasting molecular and structural adaptations in the brain. In this study, we show that tissue plasminogen activator (tPA), an extracellular protease involved in neuronal plasticity, modulates the biochemical and behavioral response to cocaine. When injected in the acute binge paradigm, cocaine enhanced tPA activity in the amygdala, which required activation of corticotropin-releasing factor type-1 (CRF-R1) receptors. Compared with WT mice, tPA−/− mice injected with cocaine displayed attenuated phosphorylation of ERK, cAMP response element binding protein (CREB), and dopamine and cAMP-regulated phosphoprotein 32 kDa (DARPP-32) and blunted induction of immediate early genes (IEGs) c-Fos, Egr-1, and Homer 1a in the amygdala and the nucleus accumbens (NAc). tPA−/− mice also displayed significantly higher basal preprodynorphin (ppDyn) mRNA levels in the NAc in comparison to WT mice, and cocaine decreased ppDyn mRNA levels in tPA−/− mice only. Cocaine-induced locomotor sensitization and conditioned place preference (CPP) were attenuated in tPA−/− mice. Cocaine exposure also had an anxiolytic effect in tPA−/− but not WT mice. These results identify tPA as an important and novel component of the signaling pathway that modulates cocaine-induced changes in neuroadaptation and behavior.     

Urokinase-type plasminogen activator and plasminogen activator inhibitor antigen in tissue extracts of paranasal sinus mucous membranes affected by chronic sinusitis and antrochoanal polyps

We examined the effect of pH on the extraction of urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor-1 (PAI-1) from paranasal sinus mucous membrane associated with chronic sinusitis and antrochoanal polyps. The specific activity of u-PA extracted with buffer at pH 7.4 was stronger than that extracted with buffer at pH 4.2. The antigen level of u-PA extracted with the acidic buffer was significantly higher than that extracted with the neutral buffer. In contrast, the difference in antigen levels of PAI-1 extracted with the acidic buffer and neutral buffer was not significant. Based on these results, we inferred that the u-PA-PAI-1 complex was extracted by the acidic buffer and the activity of u-PA was therefore decreased. Received: 22 June 1998 / Accepted: 14 October 1998     

Feasibility and logistics of MRI before thrombolytic treatment

Objectives – The study analyzes feasibility and time‐delays in Magnetic resonance imaging (MRI) based thrombolysis and estimate the impact of MRI on individual tissue plasminogen activator (rtPA) treatment. Materials and methods – Feasibility of MRI and time logistics were prospectively recorded in patients referred with presumed acute stroke over a 2 year time period. Door‐to‐needle‐times (DNT) were compared with those of patients treated with rtPA after conventional CT during the same time period, and to published open label studies. Results – We received 174 patients with presumed stroke. MRI was feasible in 141 of 161 (88%) of those requiring acute imaging. MRI supported the decision to treat 11 patients with mild symptoms or seizures, and not to treat four patients with extensive infarctions. Median ‘door‐to‐needle time’ (DNT) in MR scanned patients (70 min), did not differ significantly from DNT after conventional CT (n = 17, DNT = 66 min, P = 0.27) or the Safe Implementation of Thrombolysis in Stroke (SITS‐MOST) registry (DNT = 68 min). Conclusions – Magnetic resonance imaging can be performed in the majority of acute stroke patients without delaying treatment. MRI may affect decision making in a large proportion of patients.     

老年动脉硬化脂蛋白(a)和纤溶活化变化及临床意义

目的 :研究脂蛋白 ( a)〔L P( a)〕与老年动脉硬化疾病的关系 ,并探讨 L p( a)是否通过抑制纤溶系统起作用。方法 :对 64例老年患者及健康者进行了 L p( a)、组织型纤溶酶原激活剂 ( t-PA )及其抑制物 ( PAI-1)、纤溶酶 ( PL )、纤溶酶原( PL G)和纤维蛋白原测定 ,按疾病情况分为 3组。结果 :L p( a)水平在冠心病组、冠心病患者伴有糖尿病组明显升高 ,各组纤溶活性指标水平差别有显著。结论 :L p( a)升高是冠心病的一个独立的危险因素 ,推测 L p( a)并非主要通过抑制纤溶系统起作用。     

Localization of urokinase-type plasminogen activator, its receptor, and inhibitors in mouse forebrain during postnatal development

Proteolytic enzymes are postulated to play a role in cell migration and synapse organization during brain development. Among these, urokinase-type plasminogen activator (uPA) has been studied in neoplastic and cultured brain cells extensively. We hypothesized that uPA, its receptor, and its inhibitors would be expressed in immature glial and neuronal cells in postnatal mouse forebrain. Immature cortical neurons were immunoreactive for uPA, its receptor, and its substrate plasminogen peaking at the end of postnatal week two, consistent with the postulated role in synaptogenesis. Immunoreactivity for uPA receptor was also observed on astroglial cells in vitro. Neither it nor uPA were convincingly detected in subventricular zone precursor cells, immature white matter or pre-labeled immature cells that had been transplanted into brain. Plasminogen activator inhibitor type 1 immunoreactivity was observed on endothelia up to 12 days age, and type 2 was observed to surround immature cells. We conclude, based on the spatial and temporal distribution of immunoreactivity, that uPA and its receptor may be relatively more important for synaptogenesis, remodeling, and reactive processes than for cell migration in developing mouse brain.     

非诺贝特抑制兔脂肪组织纤溶酶原激活物抑制剂-1表达的机制

目的：观察非诺贝特对高胆固醇喂养兔脂肪组织纤溶酶原激活物抑制剂-1（PAI-1）mRNA表达的影响，并阐明其可能机制。方法：15只兔随机分为对照组、高胆固醇血症组和非诺贝特治疗组。实验的第12周末取兔皮下脂肪组织，并分离培养脂肪细胞，应用半定量逆转录多聚酶链式反应（RT-PCR）测定脂肪组织和细胞PAI-1、PPAR7和PPARα mRNA的表达。结果：高胆固醇血症组脂肪组织PAI-1 mRNA表达高于对照组（P〈0．01）。非诺贝特治疗后脂肪组织PAI-1 mRNA表达明显低于高胆固醇组（P〈0．01）。高胆固醇组脂肪组织PPARγmRNA表达高于对照组（P〈0.05），非诺贝特能降低高胆固醇饲养兔脂肪组织PPARγmRNA表达（P〈0．05），并呈剂量依赖性的降低脂肪细胞PAH和PPARγmRNA表达。3组兔脂肪组织PPARαmRNA表达差异无显著性。结论：非诺贝特能抑制高胆固醇饲养兔脂肪组织PAI-1 mRNA表达，其机制可能与下调脂肪细胞PPARγRNA表达有关。     

Monthly recombinant tissue plasminogen activator administration to implantable central venous access devices decreases infections in children with haemophilia

Summary.  Central venous access devices (CVAD) have been effectively used in the care of haemophilia patients. This is particularly true in children, who often have difficult venous access. CVAD complications (infection and thrombosis), risk factors, and complication rates, have been well-documented. However, effective interventions which decrease complication rates have not been identified. In this study, we review our experience with the use of monthly recombinant tissue plasminogen activator (rtPA) administration in haemophilia patients with fully implanted CVADs. Data on 19 haemophilia patients with 24 CVADs were available for analysis, with a total of 24 520 CVAD days. An infection rate of 0.04 infections per 1000 CVAD days and a thrombosis rate of 0.04 thrombi per 1000 CVAD days was observed. The observed infectious complication rate is at least one logarithm lower than many published CVAD infection rates in haemophilia patients who have not received rtPA administration. No bleeding complications were noted. Monthly rtPA is safe and appears to be effective in decreasing CVAD infection rates. Larger, randomized controlled studies are indicated to validate this finding.     

阿托伐他汀对糖尿病肾病患者脂蛋白（a）和纤溶酶原激活抑制物-1的影响

目的探讨阿托伐他汀对糖尿病肾病（DN）患者脂蛋白（a）[Lp（a）]、组织纤溶酶原激活物（tPA）以及纤溶酶原激活抑制物-1（PAI-1）的影响。方法60例DN患者随机分为2组，治疗组患者给予阿托伐他汀20mg每日1次睡前服用，对照组给予安慰剂，共6周，治疗前后所有患者测定血糖、肾功能、总胆固醇（TC）、甘油三脂（TG）、高密度脂蛋白-C（HDL-C）、低密度脂蛋白-C（LDL-C）、PAI-1、tPA以及尿白蛋白排泄率（UAER）进行比较。结果6周后，治疗组与对照组相比，TC、TG、LDL-C、Lp（a）、PAI-1活性及UAER下降（P〈0．05或P〈0．01），而HDLC水平和tPA活性上升（P〈0．05）。对照组治疗前后各项指标无明显变化（P〉0．05），而治疗组治疗前后上述指标有显著改变（P〈0．05或P〈0．01）。结论阿托伐他汀在降低DN患者血脂的同时，通过降低Lp（a）改善纤溶系统功能，保护受损的肾脏功能。